1. Help your friend rest their ankle, don't let them put pressure on it.
2. Put ice on the ankle to prevent swelling. Make sure you used a paper towel so that the ice isn't on their bare skin.
3. Immobilize and support the injury.
4. Elevate the ankle above the waist or heart as needed.
She should try to get a day off so she can let her muscles relax and have time to rebuild new muscle. Remember that muscle grows slowly so within 24 hours muscle starts to grow thus she should rest for at least 1 or 2 days so she doesn't exhaust her body.
Answer: The answer to your question would be 4-6 reps, 1 set.
